1. Field of the Invention
The present invention relates to an ankle brace and more particularly to an ankle brace structure which utilizes floating pivot hinges. More specifically, the present invention relates to a hinged ankle brace structure for supporting an ankle and foot while permitting partial or limited movement thereof.
2. Description of the Prior Art
Extensive studies have shown that the human knee and foot joints involve complex mechanisms which provide for extension and flexion movement as well as for rotary movement. These movements result from both a rotating and sliding movement as well as a pivoting movement in the knee and ankle joints. A detailed discussion of the ankle and foot joints appears in V. H. Frankel and M. Nordin "Basic Biomechanics of the Skeletal System" Chapters 6 and 7, Lea & Febiger, Philadelphia, 1980.
A floating pivot hinge is described in detail in U.S. Pat. No. 4,938,206, issued July 3, 1990, to Michael E. Berkeley, David P. Harris, and William C. McCune for "Floating Pivot Hinge and Knee Brace." The floating pivot hinge disclosed by Harris et al. is formed by a pair of juxtaposed hinge plates each having a pivot face in opposition to a pivot face on the juxtaposed plate with a concave groove in each of the faces. A pivot bearing ball is confined between the opposed faces and retained in the concave grooves. A spring, such as a Belleville spring or disk spring, biases the hinge plates together when the pivot bearing ball is positioned in the opposed grooves between the plates. The pivot bearing ball provides a floating pivot axis for hinge rotation of the hinge plates. The ball and concave grooves allows the hinge plates simultaneously to slide and pivot relative to each other. The pivot axis floats between the hinge plates, depending on the degree of pivoting and sliding movement in a wearer's knee joint as a result of flexion thereof.